Controller Ethernet drivers Inspiron 6400

Hi, I've problems with my controller ethernet drivers. If I put in my laptop an ethernet cable it doesn't work. Schedule is actived, my pc says it needs new drivers or an upgrade, but internet system doesn't find them and I've not a cd. So, where I can find this driver? My pc is a laptop Inspiron 6400. Please, I really need to resolve this problem! T - T